This invention is related to heaters, and in particular to heaters used to heat streams of air. Air heaters are used to create hot airflows in appliances such as dryers, room heaters, and other heating devices. Most air heaters heat airstreams by directing a flow of air over coiled resistive wires that are electrically heated to a relatively high temperature; in many cases the heated coils are red hot. This configuration provides a very high temperature difference between the wire and the air, and provides the desired rate of heat transfer into the air stream despite the relatively small surface area of the wire. In dryers the high temperatures of the heating elements can cause fire hazards, and in general it leads to relatively large inefficiencies. As energy costs continue to rise, the efficiency losses in air heaters represent a greater and greater disadvantage. A need remains for an improved technology for heating air in a variety of heating devices for home and industrial use.